1. Field of the Invention
The present invention relates, in general, to drum washing machines, and, more particularly, to a drum washing machine, and a method of controlling the drum washing machine, which improves washing performance by increasing utilization efficiency of a powdered or liquid detergent.
2. Description of the Related Art
Generally, a drum washing machine is a device that includes a water tub, which is a fixed tub, and a rotary tub having a drum shape that is rotatably provided in the water tub. The drum washing machine washes laundry using drops of water generated by a rotation of the rotary tub.
A conventional drum washing machine executes a washing process by supplying a detergent and a set amount of water together into a water tub, dissolving the detergent in the water only through an opposite directional rotation of a rotary tub, and allowing the dissolved detergent to soak through laundry. The washing process is performed thusly regardless of a type of detergent used, examples of which being powdered detergent and liquid detergent.
However, in the conventional drum washing machine, the detergent supplied into the water tub sinks to a bottom of the water tub, and dissolves in water while the rotary tub is rotated in opposite directions. Therefore, a liquid detergent may sufficiently dissolve only through the opposite directional rotation of the rotary tub. However, in the case of a powdered detergent, there is a problem in that it takes a relatively long time for the powdered detergent to dissolve, thus increasing a washing time in proportion to the time required for the sufficient dissolution of the powdered detergent. Further, in the case of the powdered detergent, it is difficult to sufficiently dissolve the powdered detergent only through the opposite directional rotation of the rotary tub even with a longer washing time. Therefore, there is a problem in that detergent deposits remain, which decreases washing performance.
Meanwhile, in the conventional drum washing machine, a detergent solution, in which a powdered detergent or liquid detergent is dissolved in the water, gradually soaks through a center part of the laundry from an outer part of the laundry by the opposite directional rotation of the rotary tub, with the outer part of the laundry coming into contact with an inner wall of the rotary tub. Therefore, it may take a relatively long time for the detergent solution to soak through to the center part from the lower part of the laundry, according to materials of the laundry. Further, the detergent solution may not sufficiently soak through the center part of the laundry according to various circumstances. Consequently, the conventional drum washing machine is problematic in that a washing time is increased and washing performance is deteriorated.